Breathing assistance device with several secure respirator modes and associated method

ABSTRACT

A breathing assistance device, capable of operating according to several respiratory modes forming a list of possible modes. The device is equipped with a mechanism for selecting a desired mode from a group of modes that can be selected. The device also includes a mechanism for realizing a configuration diagnostic of the device, a mechanism for associating with authorization level with each possible mode, according to the results of the diagnostic, with the lowest authorization level corresponding to unauthorized modes, a mechanism for authorizing only the selection of authorized modes, in such a way that selecting unauthorized modes is impossible.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/014,202, filed Jan. 26, 2011 which is a continuation of U.S.application Ser. No. 10/544,318, filed on Jun. 22, 2006, now U.S. Pat.No. 7,891,353, which is a national phase entry under 35 U.S.C. §371 ofInternational Application No. PCT/IB2003/004044, filed Aug. 28, 2003which claims the benefit of U.S. Provisional Application No. 60/498,537,filed Aug. 28, 2003, and France Application Serial No. 0210716, filedAug. 29, 2002, the disclosures of which are hereby incorporated hereinby reference.

FIELD OF THE TECHNOLOGY

This invention relates to breathing assistance devices.

More precisely, the invention relates to a breathing assistance device,capable of operating according to several respiratory modes forming alist of possible modes, and equipped with means of selecting a desiredmode from a group of modes that can be selected.

And the invention also relates to a method of implementing such adevice.

BACKGROUND OF THE TECHNOLOGY

Devices of the type mentioned above already exist.

Note that generally speaking, breathing assistance devices are designedto provide a patient with respiratory assistance, using a source of gas(oxygenated mixture) which can be connected to a turbine.

These devices can be sorted into two main categories:

(a) Ventilators. These devices are of the barometric type and realizeventilation through leakage (via vents on the mask located on thepatient side),

(b) Respirators. These devices include an expiratory valve to realizeventilation without leakage. They include a “simple” circuit (a singleduct between the patient and the device), or double.

Ventilators operate with a single duct between the device and thepatient. This single duct finishes on the patient side with a ventedmask, allowing leakage.

Ventilators generally operate in a mode of the “barometric” typeaccording to which the inspiratory and expiratory phases are mainlytriggered by pressure measurements.

Note that in general, certain breathing assistance devices can operatein a mode of the volumetric type (in which the devices forces a givenquantity of air into the duct).

The operating modes will be discussed further in this text.

Ventilators are of the CPAP type or of the BPAP type.

The CPAP type (acronym for the Anglo-Saxon denomination ContinuousPositive Airway Pressure—this type can also be designated by the acronymPPC, for Pression Positive Continue) designates ventilators with asingle pressure level.

In these ventilators, turbine speed is regulated by a pressuremeasurement in the single duct.

The single pressure setting is generally set to a value less than 20mbars (this value is expressed as excess pressure in relation toatmospheric pressure), which limits the use of such ventilators totreating superficial pathologies.

Ventilators of the BPAP type (acronym for the Anglo-Saxon denominationBilevel Positive Airway Pressure, this acronym is a registeredtrademark—and this type can also be designated by the acronym VNDP forVentilation Nasale a Deux niveaux de Pression) using the same generalarchitecture, but operating with two pressure settings (a value forinspiration pressure and a value for expiration pressure).

Regulation of the device is in this case generally controlled by:

Pressure measurement in the duct, or

Flow measurement in the duct.

This regulation can be applied to:

Turbine rotation speed (as in the case with CPAP ventilators), or

The opening of an optional rate valve which is located on the duct.

The pressure setting is generally set to a value less than 30 mbars,which allows treating pathologies that are a bit more extensive than theCPAP.

The second category is that of expiratory valve respirators.

These devices operate with, on the patient side, a mask without ventsand an expiratory valve allowing the gas expired by the patient to bedirected out of the device (for example into the surroundingatmosphere), in order to avoid reflux of the gas expired into the ductcarrying the gas to the patient.

These respirators are of the barometric or volumetric type.

Barometric respirators are regulated by a pressure setting, the settingcan have two different values.

These devices operate therefore according to the repetition of twophases: an inspiratory phase and an expiratory phase. A different valuefor the pressure setting is assigned to each phase.

These phases are initiated according to pressure or flow measurements.

A flow sensor is integrated into the respirator, in order to follow thevolume of gas inhaled by the patient.

The values for pressure settings can be higher than in the case ofventilators for ventilation via leakage: these values can reach about120 mbar.

Volumetric respirators also operate according to a succession ofinspiratory and expiratory phases.

But in this case, a volume of gas defined beforehand must be deliveredto the patient by the deliverance of a corresponding flow—the phases aretherefore initiated according to the measure of the flow inhaled by thepatient, with pressure being a resulting variable and not a controllingvariable.

The source of gas is frequently with this type of respirator a bellowsor piston apparatus.

It is however also possible for the source of gas to be a turbine. Inthis case, it is necessary to have fine control of turbine operation.

We have seen above that breathing assistance devices fall into differentcategories, and that different operating modes are associated with them.

We shall call these different operating modes “respirator modes”.

A respirator mode is thus defined by the control variables, controlledvariables, but also by the material means implemented (type of ductbetween the device and the patient, presence or not of an expiratoryvalve, of pressure sensors in different locations of the device, etc.).

Furthermore, note that there are hybrid devices, providing differentoperating modes with the same device.

WO 96/11717 demonstrates for example a device in which it is possible toselect different respirator modes, using a control panel 320.

The possibility to access different respirator modes with a singledevice is certainly interesting.

But the device can become complex to handle, because of the differentmodes that are possible.

In fact, for each respirator mode it can be necessary to adapt thedevice, by connecting/disconnecting certain parts (such as mentionedabove: type of duct, valves, sensors, etc.).

And the known hybrid devices expose patients to incoherencies between achosen mode and the configuration of the device (in particularconcerning parts that are connected to the device).

In fact, the multiplication of respirator modes on the same device alsomultiplies the risk of manipulation error, since the device can beprogrammed for a given respirator mode although the correct connectionsfor this mode are not realized.

These incoherencies at best lead to complex implementation (obligationto reconfigure the device), and at worst a danger for the safety of thepatient.

BRIEF SUMMARY OF THE TECHNOLOGY

The purpose of the invention is to provide a remedy to theseinconveniences.

In order to reach this purpose, the invention offers according to afirst aspect a breathing assistance device, capable of operatingaccording to several respiratory modes forming a list of possible modes,and equipped with a means of selecting a desired mode from a group ofmodes that can be selected, characterized in that the device includes:

means to realize a configuration diagnostic of the device,

means to associate a level of authorization with each possible mode,according to the diagnostic results, with the lowest authorization levelcorresponding to unauthorized modes,

means for authorizing only the selection of authorized modes, in such away that selecting unauthorized modes is impossible.

Preferable but not limited aspects of the method according to theinvention are the following:

means to realize a configuration diagnostic of the device are meansallowing automatic diagnostic to be realized.

the results of the configuration diagnostic include an indication of acorrectly connected expiratory valve,

the device includes means for detecting a correctly connected expiratoryvalve, said means consisting of:

-   -   means to set a pressure setting to be reached at the level of        the expiratory valve,    -   means of controlling a pressure source for the device to reach        this setting at the level of the expiratory valve,    -   means to measure a characteristic of said source of pressure        when the setting is reached,    -   means for deducing from the said characteristic the presence of        a correctly connected expiratory valve,

said characteristic of the pressure source is energy associated withturbine operation,

the results of the configuration diagnostic include an indication that aproximal pressure tap is correctly connected,

the authorization levels for modes include:

-   -   a high level corresponding to authorized modes without        restriction, and    -   an intermediate level corresponding to authorized modes, but        associated with a systematic alarm,

the device includes means for detecting a change in mode and means forlocking the device in case a new mode is detected for which the level ofauthorization is different from the one of the previously selected mode,

the device includes means for detecting a change in mode and means forlocking the device in case a new mode is detected corresponding to achange in the authorization level to a lower level,

the device includes means for detecting a change in mode and means forlocking the device in case a new mode is detected corresponding to achange in the authorization level to a level that is lower than thelevel of the previously selected mode,

the device also includes a means of unlocking that can be accessedaccording to a particular operating mode,

the possible modes include modes destined to be implemented in a“ventilator” configuration of the device, and modes destined to beimplemented in a “respirator” configuration of the device,

the possible modes include modes destined to be implemented in a“ventilator” configuration of the device, and modes destined to beimplemented in a “respirator” configuration of the device,

the AIVT mode is selectively associated with a systematic alarm in thecase where, during configuration diagnostic, no correct connection of aproximal pressure tap was detected.

According to a second aspect, the invention also offers a method forhandling the operation of said device, characterized in that the methodincludes the following steps:

realization of a configuration diagnostic of the device,

association of an authorization level which each possible mode,according to the results of the diagnostic, with the lowestauthorization level corresponding to unauthorized modes,

selective authorization of authorized modes, in such a way thatselecting unauthorized modes is impossible.

A preferable but not limited aspect of the method according to theinvention is the following:

mode authorization levels include:

-   -   a high level corresponding to authorized modes without        restriction, and    -   an intermediate level corresponding to authorized modes, but        associated with a systematic alarm.

Other aspects, purposes and advantages of the invention will appearbetter when the following description of the preferable forms forrealizing the invention are read.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustration of a breathing assistance devicein accordance with the invention; and

FIG. 2 is a block diagram illustration of a configuration diagnosticstep in accordance with one embodiment of the invention.

DETAILED DESCRIPTION

GENERAL STRUCTURE OF THE DEVICE AND POSSIBLE RESPIRATOR MODES: We shallfirst describe the means that the device includes according to theinvention, as well as the modes associated with a preferable mode forrealizing the invention.

This device is in any case a breathing assistance device, capable ofoperating according to several respiratory modes.

It is a question therefore of a perfected device, of the “hybrid” type.

POSSIBLE RESPIRATOR MODES: In a particular embodiment, the device canauthorize the following respirator modes:

Modes usually implemented with ventilators. Note that these modes aresubstantially barometric (since volumetric modes are difficult toimplement with ventilators using vented masks, which allow leakage):

-   -   S mode (spontaneous):        -   This is a mode in which the phases (inspiration and            expiration) are triggered solely by the respiratory behavior            of the patient,        -   One or several sensors (pressure, for example) are usually            used to detect the changes in the respiration of the            patient, and to consequently trigger the adequate phases,        -   It can be said that in this mode the patient “leads”, and            the device “follows”,    -   ST mode (times spontaneous):        -   This mode is a variant of the S mode in which a safety            triggering of phases is provided if the device does not            detect, in the respiratory behavior of the patient and            within a given interval of time, the elements that should            normally initiate a new phase (such elements will be called            “triggering behavior”. These triggering behaviors correspond            to values of parameters measured by the device—pressure, for            example—which are memorized in the device),        -   The safety triggering then substitutes itself for the cycle            of phases which is normally triggered by the patient,    -   CPAP mode:        -   this mode is another variant of the S mode in which the            inspiratory pressure and expiratory pressure values are            equal,    -   PAC mode (pressure is assisted and controlled):        -   in this mode, the device controls triggering of expiratory            phases since the duration of the inspiratory phases is set            via a parameter in a fixed way in the device,        -   as far as the inspiratory phases are concerned, these are            triggered by the patient (i.e. when the device has detected            a triggering behavior from the patient),        -   as with ST mode, a safety triggering of the phases is            provided if no triggering behaviour from the patient is            detected by the device within a given interval of time,    -   PC mode:        -   This mode is a variant of the PAC mode in which not only            expiratory phases, but also the inspiratory phases are            triggered by the device,

Modes that are normally implemented on respirators:

-   -   Al mode (aid for inspiration or spontaneous barometric mode):        -   This mode corresponds to modes S (and ST if a safety            triggering is provided), with an expiratory valve,    -   VPAC mode (ventilation with pressure that is assisted and        controlled or controlled barometric mode):        -   this mode corresponds to the PAC mode with an expiratory            valve,        -   phase regulation is ensured using a pressure measurement in            the duct: this mode includes a pressure regulation loop,    -   VPC mode:        -   This mode corresponds to the PC mode with an expiratory            valve,    -   AIVT mode (aid for inspiration with volume ensured):        -   This mode can be considered to be barometric as well as            volumetric,        -   It corresponds to the Al mode, with an extra disposition            concerning the volume inhaled by the patient: during            inspiratory phases, if the inhaled volume—which is followed            by the device—is less than a predetermined value memorized            in the device, the device terminates the expiratory phase in            “volumetric” mode, forcing a volume of gas to the patient            allowing the said predetermined value to be reached for this            phase,    -   VAC mode (ventilation assisted and controlled):        -   This mode is purely volumetric,        -   It corresponds to a declension of the VPAC mode in 100%            volumetric: the device operates here with a regulation loop            on the flow,    -   VC mode:        -   This mode corresponds to a declination of the VPC mode in            100% volumetric.

It thus appears in this preferable mode of realization that many modesare potentially available to the patient.

These potentially available modes will be called “possible” modes.

Note that the above modes correspond only to a preferable example forimplementing the invention.

The main principle of the invention can in this way be implemented witha different list of possible modes.

As we shall see, the invention makes it possible to safely and reliablyhandle such a device that can possible authorize several “possible”modes.

Structure of the Device—The device itself includes permanent elements,and optional elements that can be associated with the device for certainmodes. The general structure of the device is illustrated in FIG. 2.

The permanent elements include in particular:

A source of pressurized gas, for example a turbine capable of beingcontrolled in such a way as to provide a desired pressure or flow,

An inspiratory duct (that will simply be called “duct”) to carry the gasto the patient,

Sensor means to characterize the operation of the device.

These means can in particular include:

-   -   a sensor of pressure present in the duct,    -   a sensor of flow passing in this duct,

Means for handling the operation of the device. These means can inparticular include:

-   -   A user interface to allow the user (patient or doctor, for        example):        -   to select a desired mode from the modes offered in a menu.            For this purpose the device can include a keyboard, for            example,        -   to display the information and data concerning the operation            of the device. A display screen, for example, can be            provided for this purpose,    -   means of memorizing and running a program allowing a selected        mode to be implemented.        -   These means thus allow in particular to trigger the            inspiratory and expiratory phases (according to the            triggering behavior detected with the patient using sensor            means, or according to predetermined parameters memorized in            the device),    -   means allowing to realize a configuration diagnostic of the        device.        -   We will discuss the role of these means,    -   means for associating a level of authorization with each        possible mode, according to the results of the diagnostic, with        the lowest level of authorization corresponding to unauthorized        modes,    -   means for authorizing at the level of the user interface only        the selection of authorized modes, in such a way that the        selection of unauthorized modes is impossible.

The device also includes connectors that make it possible to connect:

-   -   a flexible with pneumatic control of an expiratory valve, in        order to allow such a valve to be opened and closed when it is        connected to the device,    -   a proximal pressure tap for the connection of a flexible of        which the other end is connected to the mask of the patient,        allowing pressure at the level of the patient to be determined        (this pressure is called “proximal pressure”).

The optional elements of the device include thus in particular theexpiratory valve and the flexible for proximal pressure tap.

These optional elements can be connected to the device or not, accordingto the mode selected.

Operation of the Device—The device according to the invention is thus adevice capable of operating according to several possible modes.

Each one of these modes can require the presence of specific optionalelements.

And on the contrary, it can be desired to avoid connecting certainoptional elements for certain modes.

Connecting the different optional elements to the device defines a“configuration” of the device. And the device can therefore beconfigured in different way, according to the optional elements that areconnected.

Configuration diagnostic—The invention implements a step ofconfiguration diagnostic of the device, in order to establish a list ofthe optional elements that are effectively connected to the device.

Concerning the frequency of realizing such a diagnostic:

-   -   This step of the diagnostic can be implemented each time the        device is turned on,    -   It can also be implemented every time a new mode is selected,    -   And it can also be implemented periodically in a systematic way,        for the purpose of verifying the proper configuration of the        device,    -   Note that the above-mentioned solutions can be combined.

This diagnostic step can be realized automatically, via means ofautomatic diagnostic of the device.

In this case, said means of automatic diagnostic are programmed toperform the configuration diagnostic when this is desired (see thedifferent possibilities for frequency for realizing the abovediagnostic).

Such automatic means of diagnostic allow the optional elements that areconnected to the device to be determined automatically.

In the case described here the optional elements include the expiratoryvalve and the flexible proximal pressure tap.

In order to detect the proper connection of an expiratory valve, theseautomatic diagnostic means can perform the following operations, alsoillustrated in FIG. 2:

-   -   setting the pressure setting to be reached at the level of the        expiratory valve,    -   controlling the pressure source of the device (the turbine in        the case described here) to reach this setting at the level of        the expiratory valve,        -   Note to this effect that the expiratory valve is controlled            pneumatically par the control flexible mentioned above,            since this flexible is fed by the pressure source for the            device,    -   measure a characteristic of said source of pressure when the        setting is reached,        -   This characteristic can for example be the energy absorbed            by the turbine in order to provide pressure in the duct,            allowing the pressure setting to be reached at the level of            the expiratory valve,    -   deduction, according to the said characteristic, of the presence        of a correctly connected expiratory valve,        -   if the turbine has only absorbed a small amount of energy in            order to allow reaching the pressure setting at the level of            the expiratory valve, this means that the expiratory valve            is correctly connected. If the absorbed energy is high, the            connection is not realized, or it is defective.        -   In this case two ranges of values for energy absorbed by the            turbine are predefined and memorized in the device in order            to determine respectively a range corresponding to a valve            that is correctly connected, and a range corresponding to a            valve that is incorrectly connected.

The automatic means of diagnostic include therefore in this case meansthat allow these different operations to be performed. Such means areconnected to the memory and to the programmed mentioned above.

In order to detect proper connection of a flexible for proximal pressuretap, the automatic means of diagnostic include:

-   -   A pressure sensor at the level of the connection for the        flexible for proximal pressure tap,        -   This sensor indicates the proximal pressure when the            flexible is connected,        -   This proximal pressure corresponds, when the flexible is            connected, to the pressure at the level of the duct, taking            a load loss into account (which is according to, among other            things, the length of the duct between the duct pressure tap            and the proximal pressure tap),        -   In the absence of a flexible, the proximal pressure sensor            indicates low pressure,    -   Means of comparing the values of the pressure at the level of        the duct and the proximal pressure,    -   Means allowing to establish according to this comparison if a        flexible for proximal pressure tap is correctly connected to the        device. If the difference between the two measured pressures        exceeds a predetermined threshold memorized in the device, the        automatic means of diagnostic therefore indicate that the        flexible for proximal pressure tap is not connected.

Note that in a simplified variant for implementing the invention, thediagnostic can be realized by the user himself, using instructionsprovided by the device.

In this variant, the means of the device making it possible to realize adiagnostic is a “check-list” of connections to be checked which isdisplayed on the screen when the diagnostic is required (see above forthe different possibilities of frequency for implementing thediagnostic).

In all cases, this step of configuration diagnostic for the device makesit possible to establish the list of optional elements that areeffectively connected to the device.

Assigning authorization levels to the modes Different authorizationlevels are memorized in the device.

There can be any number of levels. It must greater than or equal to two,with the lowest level corresponding as we shall see to an “unauthorized”level.

And at the end of the configuration diagnostic step, the device willautomatically associate one of these authorization levels to each of thepossible modes for the device.

In this example, three authorization levels are defined:

-   -   Level 0: unauthorized mode,    -   Level 1: authorized mode, but associated with a systematic        alarm. This is an intermediate level,    -   Level 2: authorized mode, without systematic alarm and without        restriction.

Associating a level to each mode takes place according to a given law oftransfer:

-   -   for which one input is the list of optional elements that were        detected as being correctly connected during the diagnostic        step,    -   and for which the output is the list of pairs (mode, associated        authorization level).

To implement this association of an authorization level with each mode,the device uses a means of calculation implementing a processor, whichis connected to the memory of the device.

The transfer matrix, which corresponds to the transfer function, is alsomemorized in this memory.

In the example described here, this matrix is as follows:

Mode assignment Mode coefficient S ST CPAP PAC PC AI VPAC VPC AIVT VACVC Optional Expiratory 0 0 0 0 0 2 2 2 2 2 2 Element Valve 2 2 2 2 2 0 00 0 0 0 Proximal 1 1 1 1 1 1 1 1 1 1 1 pressure 1 1 1 1 1 1 1 1 0.5 1 1

This matrix includes for each mode (each column) four mode assignmentcodes.

Two coefficients are associated with each optional element:

-   -   a coefficient that is assigned to the mode if correct connection        of the element was detected during diagnostic (top line in the        cell),    -   a coefficient which is assigned to the mode if correct        connection of the element was not detected during diagnostic        (bottom line in the cell).

A coefficient per optional element is thus associated with each mode(here then two coefficients are associated to each mode).

The level associated with each mode is then obtained by multiplying thecoefficients associated to the mode amongst themselves.

Note that this mode of “calculation” of the level associated with eachmode can be different, and any law of correspondence between thedetected optional elements and the assigned levels can be defined andmemorized in the device.

In the case shown here, we see that:

-   -   modes S, ST, CPAP, PAC, PC will be assigned the level 0        (unauthorized modes) if the expiratory valve is connected,    -   modes AI, VPAC, VPC, AIVT, VAC, VC will be assigned, on the        contrary, level 0 if the expiratory valve is not connected,    -   in the case where the expiratory valve is connected, the AIVT        mode will be assigned an intermediate level (1 instead of 2) if        the proximal pressure tap is not connected.

Selective authorization of modes—Once the assigning of an authorizationlevel for each mode has been performed, the device has in memory thecorrespondence between the modes and their associated level.

This correspondence is going to be determinant for handling theoperation of the device.

In fact, the device includes means for updating the menu of modesoffered to the user, according to the authorization levels of the modes.

In this way, a mode that is associated with level 0 will not be able tobe selected by the user.

The device can for example to this effect automatically delete theunauthorized modes from the menu of modes offered for selection, orselectively deactivate the selection keys for these unauthorized modes,in the case where selection is made by pressing a key that is dedicatedto that mode.

And the modes that are associated to level 1 (which can be the case herewith AIVT mode) can of course be selected by the user, but theirimplementation is associated with a systematic alarm that signals thatan optional element that is normally connected for this mode is notconnected.

This alarm can ring only when the mode is selected, or be maintainedduring the entire implementation of the mode.

It can be replaced with an alert message for the user.

Locking the device—We have seen above that according to theauthorization level assigned to each mode, the mode can be offered forselection or be removed from selection.

We have also seen that intermediate authorization levels can allow amode to be selected, with certain restrictions (systematic alarm).

We have also seen that the process mentioned above, that begins with aconfiguration diagnostic and that ends with the associations of levelswith modes, can be initialized at different occasions, and according todifferent methods.

We shall describe below a variant in which means for locking the deviceare provided in the case of incorrect use of the device.

When a new association of levels has been performed and the device is inservice (a mode has been selected), the device can include means tocheck that the mode that is selected is correctly associated with thelevel which allows this selection.

In this variant the device includes means of detecting that the mode hasbeen changed and means for locking the device in case a new mode isdetected for which the authorization level is different from that of thepreviously selected mode.

It is possible to implement such a locking only if the new detected modeis associated with a level that is lower than the previously selectedmode.

It is also possible to implement this locking only if the levelassociated with the newly-selected mode is the lowest level(“unauthorized” level).

Locking the device can lead to a blocking of its functions, and/or analarm, and/or automatic shut off after a lapse of time and a warning.

And it is also possible to allow a particular user to unlock the device,according to a particular operating mode that he is aware of.

This particular operating mode can be the key entry of a code using thedevice's keyboard, or a specific sequence for manipulating the keys ofthe device.

It thus appears that the invention makes it possible to efficiently,safely and reliably handle, the operation of a device likely to proposeseveral modes.

Indeed, the selective authorization of different modes as a function ofthe configuration of the device (i.e. as a function of the optionalelements effectively connected to the device) allows great flexibility,while at the same time great security of the operation of the device.

It should be noted that some devices have proposed some forms ofdifferentiated operating levels.

WO 97/06844 discloses an example of such device.

The device of this document can operate according to a “basic mode”, oraccording to an “advanced mode”.

But in this case, the selective authorizations are not derived from aconfiguration step.

Thus, the perspective of the device of WO 97/06844 is quite differentfrom the present invention.

Furthermore, the device of WO 97/06844 is not even designed to operatewith different configurations.

WO 00/51663 teaches another example of device which implies some form ofdifferent operating levels.

But here again, the different levels are not authorized as a function ofany “configuration” whatsoever (i.e. as a function of optional elementswhich would be connected on the device).

In this device indeed, the selective authorizations are open as afunction of the identity of the operator, and of his skills.

Furthermore, in any case the “authorization levels” of this last knowndevice do not correspond to different modes—they rather correspond to aselective access to different physical resources of the device (drugs,components, . . . ).

And here again, the device is not designed to operate with differentconfigurations.

It thus appear that the device according to the invention provides anoriginal and efficient solution for operating a single device indifferent modes and with different optional elements (such as a ventedmask, or an expiratory valve . . . ) connected to it, the associatedflexibility being nevertheless associated with a maximum degree ofsecurity.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. A respiratory treatment apparatus comprising: a controllable sourceof breathable gas, the source of breathable gas being adapted to couplewith optional ventilation components; and a controller coupled with thesource of breathable gas, the controller being configured to operate thesource of breathable gas in a plurality of respiratory treatment modesof operation, wherein a first mode of the plurality of respiratorytreatment modes of operation is associated with a first component of theoptional ventilation components and a second mode of the plurality ofrespiratory treatment modes of operation is associated with a secondcomponent of the optional ventilation components; the controller beingfurther configured to control a configuration diagnostic to detect apresence of at least one of the optional ventilation components, thecontroller being further configured to authorize at least one of theplurality of respiratory treatment modes of operation based on thedetection of the configuration diagnostic.
 2. The apparatus of claim 1wherein the controller is configured to control a user interface toprevent user selection of at least one of the respiratory treatmentmodes of operation based on the configuration diagnostic.
 3. Theapparatus of claim 1 wherein one of the plurality of respiratorytreatment modes of operation is a spontaneous mode.
 4. The apparatus ofclaim 1 wherein one of the plurality of respiratory treatment modes ofoperation is a VPAC mode.
 5. The apparatus of claim 1 wherein the firstcomponent comprises an expiratory valve.
 6. The apparatus of claim 5wherein the second component comprises a pressure tap.
 7. The apparatusof claim 1 wherein the controller controls the configuration diagnosticby controlling a pressure setting of the controllable source ofbreathable gas.
 8. The apparatus of claim 7 wherein the controllablesource of breathable gas comprises a turbine.
 9. The apparatus of claim1 wherein the controller is configured to initiate the configurationdiagnostic each time a new mode of operation of the plurality ofrespiratory treatment modes of operation is selected with a userinterface of the apparatus.
 10. The apparatus of claim 1 wherein thecontroller is configured to initiate the configuration diagnostic eachtime operation of the apparatus is initiated.
 11. A respiratorytreatment apparatus comprising: a controllable supply means forsupplying breathable gas, the supply means being adapted to couple withoptional ventilation components; and a processing means coupled with thesupply means, the processing means for operating the supply means in aplurality of respiratory treatment modes of operation, wherein a firstmode of the plurality of respiratory treatment modes of operation isassociated with a first component of the optional ventilation componentsand a second mode of the plurality of respiratory treatment modes ofoperation is associated with a second component of the optionalventilation components; the processing means for controlling aconfiguration diagnostic to detect a presence of at least one of theoptional ventilation components, the processing means for authorizing atleast one of the plurality of respiratory treatment modes of operationbased on the detection of the configuration diagnostic.
 12. Theapparatus of claim 11 wherein the processing means is configured tocontrol a user interface to prevent user selection of at least one ofthe respiratory treatment modes of operation based on the configurationdiagnostic.
 13. The apparatus of claim 11 wherein one of the pluralityof respiratory treatment modes of operation is a spontaneous mode. 14.The apparatus of claim 11 wherein one of the plurality of respiratorytreatment modes of operation is a VPAC mode.
 15. The apparatus of claim11 wherein the first component comprises an expiratory valve.
 16. Theapparatus of claim 15 wherein the second component comprises a pressuretap.
 17. The apparatus of claim 11 wherein the processing means controlsthe configuration diagnostic by controlling a pressure setting of thecontrollable source of breathable gas.
 18. The apparatus of claim 11wherein the processing means initiates the configuration diagnostic eachtime a new mode of operation of the plurality of respiratory treatmentmodes of operation is selected with a user interface of the apparatus.19. The apparatus of claim 11 wherein the processing means initiates theconfiguration diagnostic each time operation of the apparatus isinitiated.